Yes, I am - sorry, I should have said. As I said, it's not a major problem because I can still access what I want via programs, but it is annoying and inconvenient.
I've tried System Restore - but whatever point I pick, I am told (after the whole process) that it can't be restored to that point even though it said it could at the start (I've tried 10 different restore points).
Thanks, Technotiger. I am not proud, so anyone can feel free to insult my intelligence as much as they like if it helps me (I am learning all the time). Sadly, yes I did try using the bold print dates. It still refused to restore and, also, it refuses to allow me to set up a system-restore point of my own. This sounds like it should be a post of its own.
I posted this yesterday, so I'll leave it open for one more hour, then I will resolve and post anew (people don't read old stuff).